DESCRIPTION

RSA_generate_key_ex() generates a key pair and stores it in the RSA
structure provided in rsa. The pseudo-random number generator must
be seeded prior to calling RSA_generate_key_ex().

The modulus size will be of length bits, and the public exponent will be
e. Key sizes with num < 1024 should be considered insecure.
The exponent is an odd number, typically 3, 17 or 65537.

A callback function may be used to provide feedback about the
progress of the key generation. If cb is not NULL, it
will be called as follows using the BN_GENCB_call() function
described on the BN_generate_prime(3) page.

While a random prime number is generated, it is called as
described in BN_generate_prime(3).

When the n-th randomly generated prime is rejected as not
suitable for the key, BN_GENCB_call(cb, 2, n) is called.

When a random p has been found with p-1 relatively prime to e,
it is called as BN_GENCB_call(cb, 3, 0).

The process is then repeated for prime q with BN_GENCB_call(cb, 3, 1).

RSA_generate_key is deprecated (new applications should use
RSA_generate_key_ex instead). RSA_generate_key works in the same was as
RSA_generate_key_ex except it uses ``old style'' call backs. See
BN_generate_prime(3) for further details.